1. Field of the Invention
The invention relates to an apparatus for driving a wheelchair, more particularly to an apparatus that enables a hand-operated wheelchair to be power-driven.
2. Description of the Related Art
Conventional wheelchairs include hand-operated and power-operated ones, which are in general not compatible in construction. If the user of a hand-operated wheelchair wishes to switch to a power-operated one, he/she has to buy a new one, which is wasteful.
Therefore, the main object of the present invention is to provide an apparatus for driving electrically a hand-operated wheelchair.
Accordingly, an apparatus of the present invention is adapted for driving electrically a hand-operated wheelchair. The wheel chair includes a chair frame that has two vertical rod portions and two axle holes formed through the rod portions, respectively, and two wheels that are mounted rotatably on two opposite sides of the chair frame. Each of the wheels has a hub having two opposite sides, each of which is provided with a plurality of pairs of spokes that extend therefrom. The hub and each pair of the spokes define cooperatively a generally trapezoidal space thereamong in a respective one of the wheels. The apparatus of this invention includes two driving devices, a power supply device, and a control device. Each driving device includes a motor unit provided with a motor shaft and a transmission unit that is adapted to be mounted removably on a respective one of the wheels so as to transfer rotation of the motor shaft to the respective one of the wheels in such a manner that each of the wheels rotates at a speed smaller than that of the respective motor shaft. The power supply device is adapted to be disposed on the chair frame for supplying electrical power to the motor units. The control device controls speed ratios of the motor shafts of the motor units so as to be adapted to steer the wheelchair.